La formación de conceptos en la resolución numérica de ecuaciones no lineales

Un estudiante no necesariamente utiliza la definición cuando decide si un objeto matemático es ejemplo o contraejemplo de un concepto determinado, sino que generalmente toma la decisión basándose en una imagen que se hizo del mismo. Por lo tanto, es aconsejable comenzar la enseñanza de cada concepto presentando diversos ejemplos mediante los cuales los alumnos puedan formarse una adecuada imagen. Este trabajo tiene como objetivo presentar la secuencia didáctica que se diseñó para la comprensión de los conceptos que se hallan involucrados en la resolución numérica de ecuaciones no lineales, ofreciendo experiencias y ejemplos. También se mostrarán los resultados obtenidos tras su aplicación

Derivada y aplicaciones: La tecnología en el aula

Este trabajo forma parte de una tesis de maestría en docencia universitaria en la que se ha propuesto realizar un estudio de caso inscripto en la enseñanza y el aprendizaje de análisis matemático I en dos especialidades de ingeniería de la facultad regional san nicolás dependiente de la universidad tecnológica nacional, argentina: ingeniería Electrónica e Ingeniería Mecánica. Se analiza si incide favorablemente en el aprendizaje de dicha asignatura la incorporación de la tecnología para una adecuada visualización de los contenidos involucrados. Para ello se han confeccionado 24 pantallas interactivas con el software GeoGebra para ser utilizadas en las clases teóricas correspondientes a la unidad didáctica de “Derivada y aplicaciones”. Se investiga, además, si dicha incorporación modifica en los alumnos ciertas actitudes con respecto a la materia. En este reporte se presentan las conclusiones a las que se ha arribado con respecto a la visualización

Simulations of dispersion and deposition of coarse particulate matter

In order to study the dispersion and deposition of coarse anthropogenic particulate matter (PMc, aerodynamic diameters> 10 mm), a FORTRAN simulator based on the numerical integrator of Bulirsch and Stoer has been developed. It calculates trajectories of particles of several shapes released into the atmosphere under very general conditions. This first version, fully three-dimensional, models the meteorology under neutral stability conditions. The simulations of such pollutants are also important because the standard software (usually originating in the United States Environmental Protection Agency-EPA-) describe only the behavior of PM10 (diameter less than 10 mm). Bulirsch and Stoer integrator of widespread use in astrophysics, is also very fast and accurate for this type of simulations. We present 2D and 3D trajectories in physical space and discuss the final deposition in function of various parameters. PMc simulations results in the range of 50-100 mm and densities of 5.5 g cm-3 emitted from chimneys, indicate that for the purpose of deposition, the emission velocities are not as important as wind speed and the shape of the particles. For densities less than 2 g cm-3, the lack of consideration of buoyancy introduces important changes in the distribution of deposited PMc.Con el objeto de estudiar dispersión y deposición de material particulado grueso antropogénico (PMc, diámetros aerodinámicos > 10 mm), se ha desarrollado un simulador FORTRAN basado en el integrador numérico de Bulirsch y Stoer, que calcula trayectorias de partículas de diversas formas liberadas al ambiente bajo condiciones muy generales. Esta primera versión, totalmente tridimensional, modela la meteorología en circunstancias de estabilidad neutral. La presentación de un simulador de dispersión de este tipo de contaminantes es, además, relevante debido a que los software de uso corriente (generalmente originados en la United States Environmental Protection Agency –USEPA-) describen sólo el comportamiento del PM10 (diámetros menores que 10 mm). El integrador Bulirsch y Stoer, de difundido uso en astrofísica, resulta también muy rápido y preciso para este tipo de simulaciones. Se presentan trayectorias 2D y 3D en el espacio físico y se analiza la deposición en función de diversos parámetros. Resultados de simulaciones de PMc en el rango de 50-100 mm y densidades de 5.5 g cm-3 emitidos por chimeneas indican que, a efectos de la deposición, las velocidades de emisión del PMc no son tan importantes frente a la velocidad del viento y la forma de las partículas. Para densidades menores que 2 g cm-3, la no consideración de la flotabilidad introduce importantes modificaciones en la distribución del PMc depositado

Preferencia de registros de representación en el concepto de límite de funciones de alumnos de primer año de ingeniería

Límite de funciones se ubica en la primera unidad de análisis matemático I, en la que los alumnos necesitan desenvolverse con distintos registros de representación semiótica y realizar conversiones entre ellos para obtener una mejor comprensión del concepto. No obstante, los docentes de primer año observan la preferencia que los alumnos manifiestan en ciertas actividades de tratamiento de registros en detrimento de otras. Ante esto se analiza la preferencia de los alumnos acerca de los registros de representación semiótica y los motivos de tal inclinación. Consecuentemente se formula una propuesta de enseñanza que contempla los diversos registros en forma equitativa

Particulate matter dynamics

A substantial fraction of the particulate matter released into the atmosphere by industrial or natural processes corresponds to particles whose aerodynamic diameters are greater than 50 mm. It has been shown that, for these particles, the classical description of Gaussian plume diffusion processes, is inadequate to describe the transport and deposition. In this paper we present new results concerning the dispersion of coarse particulate matter. The simulations are done with our own code that uses the Bulirsch Stoer numerical integrator to calculate threedimensional trajectories of particles released into the environment under very general conditions. Turbulent processes are simulated by the Langevin equation and weather conditions are modeled after stable (Monin-Obukhov length> 0) and unstable conditions (L 0) e inestabilidad (L < 0). Se presentan diversos casos estudiados en base a simulaciones tipo Monte Carlo y se discute el efecto de las condiciones meteorológicas sobre la deposición final de estas partículas

Invariant NKT cells contribute to chronic lymphocytic leukemia surveillance and prognosis

Chronic lymphocytic leukemia (CLL) is characterized by the expansion of malignant CD5(+) B lymphocytes in blood, bone marrow and lymphoid organs. CD1d-restricted invariant Natural Killer T (iNKT) cells are innate-like T lymphocytes strongly implicated in tumor surveillance. We investigated the impact of iNKT cells in the natural history of the disease both in Eμ;-Tcl1 (Tcl1) CLL mouse model and 68 CLL patients. We found that Tcl1-CLL cells express CD1d and iNKT cells critically delay the disease onset, but become functionally impaired upon disease progression. In patients, disease progression correlates also with high CD1d expression on CLL cells and impaired iNKT cells. Conversely, disease stability correlates with negative/low CD1d expression on CLL cells and normal iNKT cells, suggesting an indirect leukemia control. iNKT cells indeed hinder CLL survival in vitro by restraining CD1d-expressing Nurse Like Cells, a relevant pro-leukemia macrophage population. Finally, multivariate analysis identifies iNKT cell frequency as independent predictor of disease progression. Together, these results support iNKT cell contribution to CLL immune-surveillance and highlight iNKT cell frequency as prognostic marker for disease progression

Carotenoid Derivates in Achiote (Bixa orellana) Seeds: Synthesis and Health Promoting Properties

Bixa orellana (family Bixaceae) is a neotropical fast growing perennial tree of great agro-industrial value because its seeds have a high carotenoid content, mainly bixin. It has been used since pre-colonial times as a culinary colorant and spice, and for healing purposes. It is currently used as a natural pigment in the food, in pharmaceutical, and cosmetic industries, and it is commercially known as annatto. Recently, several studies have addressed the biological and medical properties of this natural pigment, both as potential source of new drugs or because its ingestion as a condiment or diet supplement may protect against several diseases. The most documented properties are anti-oxidative; but its anti-cancer, hypoglucemic, antibiotic and anti-inflammatory properties are also being studied. Bixin’s pathway elucidation and its regulation mechanisms are critical to improve the produce of this important carotenoid. Even though the bixin pathway has been established, the regulation of the genes involved in bixin production remains largely unknown. Our laboratory recently published B. orellana’s transcriptome and we have identified most of its MEP (methyl-D-erythritol 4-phosphate) and carotenoid pathway genes. Annatto is a potential source of new drugs and can be a valuable nutraceutical supplement. However, its nutritional and healing properties require further study

Arsenic and Boron Hydrogeochemistry behaviour during Managed Aquifer Recharge Operations.

The Cornia Valley aquifer system (Tuscany, Italy) is the main source for irrigation, industrial purposes, and for potable water supply for the zone and the Elba island. Sixty years of its overexploitation caused a remarkable potentiometric drawdown accompanied with a wide seawater intrusion and a severe degradation of the quality of the groundwater (Rossetto et al., 2018; 2019). In the early 2000s, extensive research regarding anomalous high concentrations of Boron in the Cornia Valley was carried out. These studied the hydrochemistry of the area, determining also anomalous high concentrations of Arsenic (Pennisi et al., 2009). In addition, one of the biggest schemes treating Arsenic for drinking water started operating with other two plants for Boron (Comune di Suvereto, 2013). Furthermore, in 2015 the LIFE REWAT project was started in order to set a strategy to recover and improve the availability of water in the area through a series of technical and social interventions (Rossetto et al., 2018). Within LIFE REWAT, Managed Aquifer Recharge (MAR) was identified as a solution to counterbalance the stressed hydrologic system. Thus, a pilot MAR scheme infiltrating harvested rainwater from the Cornia River was implemented. It is provided by a hi-tech high-frequency automated and remotely controlled system for operating the plant and monitoring water quantity and quality. This system is supported by the data gathered from different sensors installed in the area, recording into a database. Additionally, discrete groundwater sampling takes place monthly (Rossetto et al., 2018; 2019). The database contains recordings from two consecutive hydrological years. The first year measurements and samplings were done under natural recharge conditions, while during the second year the MAR scheme was under operation. This initial data provides insights on concentration variations of Boron and Arsenic after one-year operation of the MAR scheme. However, the main processes involved still need to be understood. Therefore, long-term and short-term dedicated field experiments are designed to analyse the induced variations. This work presents a model based hydrogeochemical approach for the behaviour analysis of these elements under MAR operations to determine the transiency of these concentration changes

The commodity nature of labour-power

Some recent Marxist contributions, among them the so-called New Solution to the transformation problem, call into question the idea of labour-power as a fully-fledged commodity. Yet, the rejection of the commodity nature of labour-power compromises Marx´s whole explanation of the origin of surplus-value on the basis of the exchange of equivalents. It can be shown, however, that it is possible to offer a positive case for the commodity-nature of labour-power which is consistent with Marx´s broader dialectical investigation of the determinations of the value-form. This requires building upon the arguments that Marx explicitly put forward in his economic works, but also going beyond them, albeit on the basis of those arguments themselves. Furthermore, this novel approach that treats the reproduction of labour-power as a commodity determined by the self-valorisation of capital proves to be very valuable to shed light on two classic Marxist controversies, namely: the debate on domestic labour and the one on skilled labour.Fil: Starosta, Guido. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Economía y Administración; ArgentinaFil: Caligaris, Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Centro de Investigaciones sobre Economía y Sociedad en la Argentina Contemporánea; Argentin

Epidemiological surveillance of trachoma in a school in an urban area in Southeastern Brazil

INTRODUCTION: Epidemiological surveillance activities undertaken after the detection of an active trachoma case in the APAE-SP are described. MATERIAL AND METHOD: A total of 1,009 pupils, employees and household contacts had an eye examination. Treatment control was carried out at the institution 4 times at 45 day-intervals. RESULTS: The overall prevalence was of 5.9%, 5.1% being of follicular trachoma (TF), 0.3% of intense trachoma (TF/TI) and 0.5% of cicatricial trachoma (TS). At the first control exercise 45.5% of the trachoma cases had no signs of the disease and 40.0% underwent treatment. At the last control exercise 20% were found to have been cured with no vestigial scars. Non-attendance was of 38.2%. The distribution of secondary cases showed great dispersion, suggesting dissemination throughout Greater S. Paulo . DISCUSSION AND CONCLUSIONS: The trachoma control activities do not show satisfactory results, perhaps due to the prolonged duration of the treatment and follow up. The development of strategies of clinical intervention should be implemented for better control of the disease.OBJETIVO: Verificar as condições de vigilância epidemiológica do tracoma desencadeadas a partir da detecção de um caso de tracoma inflamatório na APAE - SP. MATERIAL E MÉTODO: Foram submetidos a exame ocular 1.009 pessoas entre alunos, funcionários e comunicantes intradomiciliares. Os controles de tratamento foram realizados em uma instituição, por 4 vezes, em intervalos de 45 dias. RESULTADOS: A prevalência total foi de 5,9%, sendo 5,1% de tracoma folicular (TF), 0,3% de tracoma folicular intenso (TF/TI) e 0,5% de tracoma cicatricial (TS). No primeiro controle 45,5% dos casos apresentou alta clínica e 40,0% manteve tratamento. No último controle 20,0% apresentou alta curado sem cicatrizes. A taxa de faltosos alcançou 38,2%. A distribuição espacial dos casos secundários mostrou ampla dispersão na Grande São Paulo, indicando que o tracoma deve estar disseminado por toda a região. DISCUSSÃO/CONCLUSÕES: As ações de controle do tracoma não apresentaram resultados satisfatórios, provavelmente devido ao prolongado tempo de tratamento e acompanhamento. Estratégias de intervenção clínica devem ser desenvolvidas para melhor controle da doença.Secretaria de Estado da Saúde (SES). São PauloSES. São PauloUniversidade Federal de São Paulo (UNIFESP)APAESecretaria Municipal de Saúde. São PauloUNIFESPSciEL